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author | Peter Maydell <peter.maydell@linaro.org> | 2022-05-05 11:18:42 +0100 |
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committer | Philippe Mathieu-Daudé <f4bug@amsat.org> | 2022-06-11 11:36:14 +0200 |
commit | 0c285e01280d9bccda36717bad369082356cf8f4 (patch) | |
tree | 5b0844921d2e40f74add79d1efbbb401f745af36 /hw/block | |
parent | 8e0e23445acdf1cfbe7714f685c4a7404b3fa467 (diff) | |
download | qemu-0c285e01280d9bccda36717bad369082356cf8f4.zip qemu-0c285e01280d9bccda36717bad369082356cf8f4.tar.gz qemu-0c285e01280d9bccda36717bad369082356cf8f4.tar.bz2 |
hw/block/fdc-sysbus: Always mark sysbus floppy controllers as not having DMA
The sysbus floppy controllers (devices sysbus-fdc and sun-fdtwo)
don't support DMA. The core floppy controller code expects this to
be indicated by setting FDCtrl::dma_chann to -1. This used to be
done in the device instance_init functions sysbus_fdc_initfn() and
sun4m_fdc_initfn(), but in commit 1430759ec3e we refactored this code
and accidentally lost the setting of dma_chann.
For sysbus-fdc this has no ill effects because we were redundantly
also setting dma_chann in fdctrl_init_sysbus(), but for sun-fdtwo
this means that guests which try to enable DMA on the floppy
controller will cause QEMU to crash because FDCtrl::dma is NULL.
Set dma_chann to -1 in the common instance init, and remove the
redundant code in fdctrl_init_sysbus() that is also setting it.
There is a six-year-old FIXME comment in the jazz board code to the
effect that in theory it should support doing DMA via a custom DMA
controller. If anybody ever chooses to fix that they can do it by
adding support for setting both FDCtrl::dma_chann and FDCtrl::dma.
(A QOM link property 'dma-controller' on the sysbus device which can
be set to an instance of IsaDmaClass is probably the way to go.)
Fixes: 1430759ec3 ("hw/block/fdc: Extract SysBus floppy controllers to fdc-sysbus.c")
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/958
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20220505101842.2757905-1-peter.maydell@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Diffstat (limited to 'hw/block')
-rw-r--r-- | hw/block/fdc-sysbus.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/hw/block/fdc-sysbus.c b/hw/block/fdc-sysbus.c index 57fc877..86ea51d 100644 --- a/hw/block/fdc-sysbus.c +++ b/hw/block/fdc-sysbus.c @@ -94,18 +94,14 @@ static void fdctrl_handle_tc(void *opaque, int irq, int level) trace_fdctrl_tc_pulse(level); } -void fdctrl_init_sysbus(qemu_irq irq, int dma_chann, - hwaddr mmio_base, DriveInfo **fds) +void fdctrl_init_sysbus(qemu_irq irq, hwaddr mmio_base, DriveInfo **fds) { - FDCtrl *fdctrl; DeviceState *dev; SysBusDevice *sbd; FDCtrlSysBus *sys; dev = qdev_new("sysbus-fdc"); sys = SYSBUS_FDC(dev); - fdctrl = &sys->state; - fdctrl->dma_chann = dma_chann; /* FIXME */ sbd = SYS_BUS_DEVICE(dev); sysbus_realize_and_unref(sbd, &error_fatal); sysbus_connect_irq(sbd, 0, irq); @@ -138,6 +134,16 @@ static void sysbus_fdc_common_instance_init(Object *obj) FDCtrlSysBus *sys = SYSBUS_FDC(obj); FDCtrl *fdctrl = &sys->state; + /* + * DMA is not currently supported for sysbus floppy controllers. + * If we wanted to add support then probably the best approach is + * to have a QOM link property 'dma-controller' which the board + * code can set to an instance of IsaDmaClass, and an integer + * property 'dma-channel', so that we can set fdctrl->dma and + * fdctrl->dma_chann accordingly. + */ + fdctrl->dma_chann = -1; + qdev_set_legacy_instance_id(dev, 0 /* io */, 2); /* FIXME */ memory_region_init_io(&fdctrl->iomem, obj, |